Multiple plunger variable delivery pump



April 15 1941., F. L. DAVIS. JR

MULTIPLE PLUNGER VARIABLE DELIVERY PUMP Filed Jan. 17, 1939 6 Sheets-Sheet 1 fly] ' IN VE/VTOR v By F/"(J/ML liar/5J1 A TTORNE Y April 15, 1941. F. L. DAVIS, JR 2,238,252

MULTIPLE PLUNGER VARIABLE DELIVERY PUMP Filed Jan. 17, 1959 6 Sheets-Sheet2 a um ATTORNEY April 15, 1941. F. L... DAVIS, JR

MULTIPLE PLUNGER VARIABLE DELIVERY PUMP 6 Sheets-Sheet 5 Filed Jan. 17, 1939 Y IN VE/VTOR .F/"an/r Z. [)a 105,15".

.4 TTORNE V April 15, 1941. F. L. DAvas, JR 292387252 MULTIPLE PLUNGER VARIABLE DELIVERY PUMP Filed Jan. 17, 1939 6 Sheets-Sheet 4 A TTORNEY April 15, 1941.

F. L. DAVIS, JR

MULTIPLE PLUNGER VARIABLE DELIVERY PUMP 6 Sheec s-Sheet 5 Filed Jan. 17, 1959 IN VENTOR Fran/(5.5a V/SJ.

ATTORNEY F. L. DAVIS, JR

MULTIPLE PLUNGER VARIABLE DELIVERY PUMP April 15,1941.

Filed Jan. 17, 1939 6 Sheets-Sheet 6 h A x INVENTOR Wan/ff, Dar/Si, (7/? Q ATTORNEY Patented Apr. 15, 1941 7 2,238,252 1 MULTIPLE PLUNGER VARIABLE DELIVERY PUMP Frank L. Davis, Jr... Kenilworth, N. 1., assignor of one-halt to Anthony William Dcllcr, New York,

Application January 17, 1039, Serial No. 251,291

(or. ins-11a) 4 Claims.

The present invention relates to pumps, and, more particularly, to a multiple-plunger, variable stroke, high pressure pump or improved character.

Heretofore, pumps of the variable stroke and variable delivery type have generally been provided with packless plungers operated at a short strokeat high speeds and with ported valving. Pump bodies and pluugers revolved in unison, and, as a rule, 011 has been used as a fluid pressure medium. These conventional pumps could be divided into two principal groups, the first of which was the so-called swash plate" type in which a plate capable of a variable angular setting with relation to the axis of revolution was provided while the other was or the radial type having a plurality of plungers arranged like the spokes of a wheel and actuated by a driving member of variable eccentricity. In the swash plate types the plungers were disposed parallel to the drive axis and grouped around the same, some types of the pump bodies discharging lengthwise. the pump bodies thrusting against a distributing valve plate, while the other type of pump bodies discharged radially inward to a sta-- tionary ported shaft around which the pump bodies revolved. The drive from the swash plate was provided through ball end connecting rods,

' one end of said rods being usually seated in the trunk pistons or plungers, the other in sockets in the swash plate. In the radial type of pumps, the pump bodies and plungers revolved around central ported shafts into which the pumps discharged. The plungers were usually driven by pivoted shoes thrusting against an adjustable guide member. tional variable delivery pumps were rated for not over 3000 lbs. per sq. in. maximum delivery pressure and were hardly capable of more than 2500 lbs. per sq. in. in practical. operation for any length of time. The design of these pumps was so complicated and the adjustment of the cooperating parts. so critical that the units generally had to be shipped back to the factory for even slight adjustments and repairs. Another disadvantage of conventional variable delivery pumps was that they employed packle'ss plungers and pumps having their suction and discharge through ports in stationary parts registering with ports in revolving parts so that extremely small running clearances between the cooperating parts were required in order'to prevent exces-. sive leakage from high to low pressure areas and loss in volumetric efliciency. Obviously, these.

small clearances constantly increased due to Practically all of these conven-' service wear, particularly if the fluid medium contained small amounts of dirt or grit producing an abrasive effect, so that frequent replacements were necessary. The high speed 01 the reciprocating parts and the high velocities of the compression fluid through restricted passages frequently caused an objectionable hum particularly in cases when the rhythmic vibrations in the pump mechanism coincided with those of the foundation plates or tanks on which the pumps were generally mounted, necessitating the subsequent addition of damping means or devices to reduce the hum and the vibrations and to keep them within permissible limits.

Due to the internal leakage inherent in the conventional variable delivery pumps it was absolutely necessary to employ oil as fluid pressure medium, since it was not permissible to allow any other fluid to escape into the lubricating oil provided in the casing of the running mechanism and distributed by means of splash lubrication. The use of oilas a pressure medium caused great variations in the output and the efliciency of the pumps. in view of the fact that the viscosity of oil varied quite considerably with its temperature. Thus, the temperature of the oil and the emciency of the pump varied considerably after the pump was running for a time and became heated up, necessitating to either employ a very large body of oil or the introduction of special cooling devices or coils at additional expense. The oilwas expensive and formed a definite fire risk in case of any external leakage particularly in hot forging presses. Great difliculties and inconveniences were also experienced with the pressure limitations inherent in the conventional variable delivery pumps, The increase in pressure caused substantial increase in the leakage through the unavoidable clearance. Moreover, it was extremely difficult to provide suiflcient bearing area on shoes and ball end connecting rods to bring the unit bearing pressures down to practical limits. Rubbing velocities were high and generated excessive amounts of heat. It is also to be noted that where ball ends were seated in plungers they were limited by securing means to about one half of the plunger diameter, or one fourth of its area so that whatever pressure was built up against the face of the plunger there was four times as high bearing pressure which finally limited the obtainable maximum pressures by the ability of maintaining lubrication. Furthermore,

in the conventional pumps of the radial'type where the resultant of pressure reaction acted time, severe bending stresses occurred between the supports of the revolving pump bodies and caused binding on the fixed shaft and unequal running clearances around the shaft. When it was attempted to remove the binding effects by increasing the clearance, the increase in leakage was so great that the efllciency of the pump was greatly decreased.

A further important disadvantage of conventional variable delivery pumps was that little variation was practicable in the size of the cooperating parts in order to obtain different pumping characteristics in a pump of given size. Therefore, a relatively large number of different models of the same. family of design was necessary to cover the range of requirements on the market, and even so, it was hardly practical to provide single units having an output over 50 H. P. The above considerations clearly indicate that the art was confronted with a problem of great complexity and importance. Although various s ggestions and proposals have been made to solve the outstanding problem, none, as faras I am aware, of these various suggestions and proposals was completely satisfactory and successi'ul when carried into practice on a practical and industrial scale.

I have discovered that the problem may be solved in a remarkably simple manner.

It is an object of the present invention to provide a variable stroke and delivery pump of improved character which substantially eliminates all of the above disadvantages and inconveniences of conventional variable stroke pumps.

It is another object or the present invention to provide a multiple plunger, reciprocating, power-driven pump which permits changing the length of the stroke and the rate of delivery from zero to a predetermined maximum while the pump is rimning continuously. a

Another object of the invention is to provide a variable stroke pump capable of generating considerably higher pressures than was possible heretofore by either the conventions swash pla or by the radial, eccentrlcally displaceable types.

It is a further object of the present invention to provide an improved multi-plunger pump of the variable delivery type Which is capable of using water or other preferred liquids as compression fluids and which is not restricted inits operation to oil, as are all of th conventional pumps.

Still another object of the invention is to provide a multi-plunger pump in which the operating mechanism is substantially separated from the detachable pump body so that pump bodies of different delivery capacities and with larger or smaller plungers may be attached to the same operating mechanism.

The invention also contemplates a variable delivery pump which is simple in construction and relatively inexpensive and fool-proof in its operation.

Other objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a perspective view of a pump embodying the principles of the present invention:

Fig. 2 illustrates a vertical sectional view of the pump shown in Fig. 1, the operating parts being shown in full stroke" position;

Fig. 3 is a section taken on line 3-4 of Fig. 2;

Fig. 4 depicts a section taken on line 4-4 of Fig. 2;

Fig. 11 is a top plan view of the pump body of a modified embodiment of the present invention; Fig. 12 is a section taken on line l2--l2 of Fig. 11, and

Fig. 13 shows a section taken on line l3-l'l of Fig. 11.

Broadly stated, according to the principles of the present invention I provide a vertical, powerdriven, pump having a plurality of reciprocating plungers the length of the stroke of which may be varied within predetermined limits. I also provide an enclosed operating mechanism for the pump while the pump body proper is detachably mounted on the top of the casing of the operating mechanism. I prefer to provide a pump body of one-piece construction, made, for example, of forged steel to be able to resist very high pressures and fit this pump body with packed plungers and poppet valves. The main stroke producing mechanism operatively associated with the plungers comprises a wobble plate inclosed in the casing and suspended from a heavy universal Joint located in the center of a combined cross head guide and cover to the easing. Around the rim of the wobble plate are sockets for housing one end of ball-ended connecting rods, the other ends of said rods being housed in cylindrical cross heads to which the plungers are attached. Projecting downwardly from the wobble plate, I provide a tapered spindie to which power is applied to cause the wobble plate to oscillate universally about the center of .the universal joint whenever the spindle is in an ofi-center position, that is at an angle to the vertical axis, acting as a single throw crank of variable radius.

The power for driving the wobble plate may be applied through a heavy tired wheel mounted with a roller bearing between on the spindle near to its lower end. The wheel is embraced between two fiatv faces on thrust blocks carried around by a hollow rotor of cylindrical shape. A large bevel gear attached to the upper portion of the rotor meshes with a bevel pinion having a shaft extension projecting to the outside of the casing where any suitable source of power having constant speed may be applied to drive the pump. To move the spindle oi! center, I provide a linkage between a ball bearing mounted collar on the lower end of the spindle and a cylindrical cross head sliding up and down in a bore in the lower portion of the rotor. It is to be observed that from about stroke to full stroke this linkage is self locking so long as the tangent of angle thrust on the cross head is less than the coeillcient of friction between the cross head and the rotor in which it slides. Below this point the reaction from the spindle "takes charge and tends to force the crosshead downwards, resisted by the forked lever and the control shaft. By means of a key and keyway, the crosshead is caused to revolve in unison with the rotor. To actuate the crosshead, a non rotating shaft with ball. thrust bearings projects through the center of the crosshead and its lower end is provided with a fork, straddling a forked lever with pin and sliding bloc-k connection between them. This forked lever is keyed to a rocker shaft capable of a limited oscillation in bushed bearings arranged in supports forming part of the casing, the shaft extending to the outside of the casing. A strokecontrolling mechanism of any desired form may be attached to the outer end of the rocker shaft. This stroke controlling mechanism may be mancal and controlled by the operator, or may be of an automatic characterresponding to changes in pressure in the discharge line. In the latter case a plunger may be provided which is displaceable by the discharge pressure against the pressure of an adjustable spring. The spring action holds the pump on full stroke until some predetermined pressure is reached. When the pressure is further increased, the plunger will overcome the resistance of the spring and will progressively shorten the stroke until the delivery ceases at some other predetermined pressure. The plunger "will maintain this condition until the pressure drops, for example due to opening of release valves in the system, which causes the spring action to predominate and to again increase the stroke.

The. entire driving mechanism is preferably ermlosed in a casing where it is protected and where provision may be made for copious lubrication by means of a small oil circulating pump. The oil circulating pump maybe driven by some moving part of the pump mechanism taking its oil supply from the lower portion of the casing which acts as a sump. The oil is fed to channels in the highest part of the casing and through a suitable leaders and overflows cascades downto the sump again. A plurality of convenient hand holes having'detachable covers are provided in the casing for making the inner mechanism readily accessible for the purposes of adjustment and inspection.

The invention will now be more fully described to those skilled in the art in connection with the accompanying drawings.

Referring now to the drawings, a preferred embodiment of the principles of my invention is illustrated. The pump shown in the drawings is a vertical pump in which a plurality of plungers reciprocates up and down and in which most of the parts are symmetrically disposed about a vertical axis. At the top of the structureis located a pump body I of one piece construction having a squareshaped lower portion 2 extending approximately one-third of the height of pump body. The square portion 2 is surmounted by two cylindrical portions 3 and 4 of successively reduced. diameter. In this pump body a plurality of, pumping chambers 5 of cylindrical form are provided having vertical axes parallel to the central axis of the pump and being uniformly and equidistantly spaced therefrom. Although eleven pumping chambers are illustrated in the present embodiment, obviouslyany other suitable plurality of chambers may be provided, preferably of an odd number. Asthose skilled in the art know, the larger the number of the pumping chambers, the smoother is the delivery and the less are any pulsations noticeable. Pumping chambers 5 are provided with conventional guide bushings 6, a compressible packing medium I and with glands 8 for preventing leakage p st the plungers' 9 which they encircle. Glands 8 may be provided with studs or bolts (not shown) for compressing the packing, or, if desired, the threaded type of glands may be'u'sed.

To secure a pumping action and to govern the flow of liquid, suction check valves I0 and discharge check valves I I are provided, one for each pumping chamber, and "wing-guided in inserted seats I2. These valves are disposed in circular paths around the central axis, their axes being vertical and their spacing corresponding to that of the pump chambers and located in a radial plane with the same. Suction valves I0 are located at a greater radius than plungers 9 and at a lower level than discharge valves II. The latter are located above and axially in line with the plungers. The individual suction valves ,seat over passages l3 leading downwardly to a common compartment having the character of an annulargroove formed in the under side of the pump body and provided with a suitable closure, H, which may be either permanent, as illustrated, or, if desired may be of the bolted type with a gasket. Suction compartment i5 has a passage I6 leading therefrom to the outsidepf the pump body where connection maybe made to the source of fluid supply. From the chambers II above the suction valves I0 there are horizontal passages I8 provided, connecting with pumping chamber 5. From the pumping chamber 5 vertical passages lead to the under side of discharge valves II.- From above discharge valve I-I horizontal passages I9 lead in a radial direction to a common central chamber 20, discharging upward through a suitable connection to delivery pipe 2i. The chambers above the valves are preferably provided with removable closures 22 of the screwed plug type having packing washers 23 under circular ledges 24 at the top of plug 22. By removing these plugs, ac-

cess may be had to the valves for removal or grinding in of the seats, whereby the sealing effect or worn or scored seats may .be restored to their original effectiveness.

The extensions of the rectangular lower portion of pump body 2 beyond the cylindrical portions 3 and 4 are pierced to receive extensionsof heavy shouldered studs 25 with nuts 26 for the purpose of securing the pump body to other portions of the structure and to sustain and transmit the sum of the vertical reactions due to the pressure generated by the plungers when on upward or discharge stroke. As illustrated in the drawings, four of these studs are provided,

one in each corner of the pump body. Due to the shouldered type of studs used, the enlarged portions being all of the same length, they retain the pump body in a level and-parallel relationship to the top portion of the structure containing the operating mechanism to be described hereinafter.

Next in order below the pump body I and forming a detachable coverto the main casing is an element provided, in the following referred to as the dome 21. In addition to serving as a cover for the main casing, dome 21 has several additional functions. Thus, as it will be described more fully hereinafter, the dome acts as a guide for the plunger holding members, forms points of attachment for the shoulder studs 25, and provides a support from which the main wobble plate is suspended. The dome is of relatively rugged proportions as it has to transmit the full load reactions from pump body I to wobble plate 28. In form the dome has a lower portion square in plan outline and corresponding to the dimensions of the pump body I above. An approximately truncated cone formation is rising from this rectangular portionsaid formation being highest in the center and having a central circular recess 29 on its under side. At"greater radius than the central circular recess, dome 21 is pierced with cylindrical holes 53, with rims raised above the surface of the truncated conical portion of the dome, said holes corresponding in number to and axially located in line with pump chambers 5 in pump body I, above. Dome 21 is also pierced with a central hole through which projects a stem 3Ia of reduced diameter prolonged upwards from a disk-like portion 31 centered in the dome recess 29 having two lugs or ears 32 projecting downwards therefrom forming a fork serving as one of the members of a universal joint. Between the jaws 32 of forked member 3| is a rectangular block 33 provided, pivoting on two pins 34 projecting inwardly from the jaws. Two other pins 35 also project into the same block 33 at right angles to the first pair of pins, the axes of all four pins being in one plane and their common intersection occurring in the central axis of the pump. All four pins are embraced by roller or ball bearings 36 housed in recesses 31 in the sides of block 33 to reduce friction under load to a minimum.

The second set of pins 35 is secured in lugs or ears projecting upwards from a wobble plate" 26 which forms the principal member of the stroke producing mechanism. The main portion of wobble plate 28 is of a saucer shape, and

is provided with a rim 38 having a flat upper surface and blending into a recessed hub 39 towards the center, the hub in turn merging into a tapered spindle 46 extending downwards. Him 38 is pierced with cylindrical holes 4| corresponding in number and spacing to holes in the pump body I and the dome 21, above. These holes are provided for securing detachable sockets 42 by means of threaded stems 43 projecting through these holes and provided with nuts 44 in faced recesses on the under side of rim 38. Sockets 42 provide spherical bearings, the centers of which are in the same plane as the pins 35 in the universal joint, for taking the thrust from ball ended connecting rods 45 the other ends of which are housed in similar seats in cylindrical sliding members or cross heads 46, moving up and down in the guides in the dome. Both the sockets 42 and crossheads 46 are provided with identical split bushings 41 and screwed retaining rings 46 for taking tension loads in the connecting rods. Threaded rings 49 serve as means for adjusting the running clearance on bail ends 49 and have small set screws (not shown) in the rim to prevent the rings from unscrewing durlng operation.

The upper ends of cross heads 46 are provided with cylindrical recesses 50 having flat bottoms against which abut the lower end of pumping plungers 9. This lower end is provided with a circular ledge against the upper side of which abut screwed rings 5| threaded into crossheads 46 whereby plungers 9 are retained in position against suction and packing friction pull. A small amount of lateral clearance is provided to allow for possible machining inaccuracies in the alignment of the pumping chambers and crosshead guides, each member assuming its own centering before final clamping in place. Plungers 9 are embraced by downwardly sloping light shields 52 of greater outside diameter than the raised rim around crosshead guides 53 in dome 21. These shields are provided in such a position as to clear other parts throughout the full range of the stroke. Shields 52 are retained in place by snap rings 54 immediately above the shields and partly resting in a groove around the plunger. The function oi these shields is to act as sheds'for any leakage of the pressure fluid, for example water, that might occur through pump packing gland and run down the plunger where it will have to spread out and fall over the outer edge clear of crosshead guide 53. This is desirable in order to prevent the water from gaining access to the casing and from interfering with the internal oiling arrangements.

Referring now to the "wobble plate spindle 49, two distinct members are provided on its lower end, both rotatably mounted by means of suitable roller or ball bearings. The upper or thrust wheel 55 is a simple heavy ring or tire embracing roller bearing 56 and provided with a flanged lip 51 and detachable plate 59 for retaining the outer raceway of the bearing. This wheel serves to transmit the driving torque applied in a direction perpendicular to the plane of the drawing, whenever the axis of spindle 40 is in any position other than perpendicular. The lower member or collar 59 embraces outer raceways 60 of ball bearings and is pierced in a horizontal direction to one side of the spindle axis through which extends a cylindrical pin 6|. The function of collar 59 is to transmit a force applied in a direction parallel to the plane of the drawing tending to move the spindle axis away from the central or perpendicular position to any intermediate position, and to retain it there as long as it is desired. The magnitude of the force act ing through collar 59 is considerably less than the force acting through wheel 55.

The extension of pin 6| through collar 59 passes through holes in the tips of a forked link 62. The other end of link 62, which is also forked, is pierced for reception of a similar pin 63 in a sliding crosshead. This crosshead 54 of substantially cylindrical shape having its axis coinciding with the pump axis has a portion of its rim 65 extending upward with a pierced lug 66 for receiving link pin 63. This rim extension 65 is carried somewhat beyond link pin 63 so that the line of thrust reaction from link 62, when projected, falls inside the bearing area to avoid. any upsetting or cramping tendency on the part of the crosshead 64. A longitudinal keyway 61 and key 68 are provided in the outer surface meshing with keyway 69 in an adjacent bearing surface 85.

The central portion of crosshead 64 is pierced by a. cylindrical hole 10 having suitable recesses for reception of two-way thrust ball bearings 1| which in turn are embrace'd and are secured in place by a threaded lock nut 13, on a central, downwardly extending shaft 14 having its lower end expanded into a forked portion 15. Extending into the slot in the above forked terminal of shaft 14 is another fork 16 at the end of a lever 11 capable of oscillation to a limited extent in a vertical plane and pivoting about the horizontal axis of and in unison with a rocker shaft 18. Rocker shaft 18 is extended through the main casing where the desired controlling means may be attached thereto. As it is clearly shown in Fig. 9 with the unequal size bushings 19-190. and step down diameter of rocker shaft 18, it may be assembled to project through either side of the casing, as desired. Lever 11 by extending into slot 88 in forkedshaft I4 prevents the latter from rotating while it remains free to be moved up and down. To transmit forces from lever 11 to shaft 14, a pin 8| passes horizontally through both members intersecting the pump axis and also passing through a block 82 slideable in forked lever 11 whereby surface contact in preference to line contact is provided between the several parts.

Surrounding the lower end of wobble plate spindle 48, the forked link 62, crosshead 84 and forked shaft 14, is arranged a barrel shaped rotor 83 having cylindrical portions of varying diameter and pierced vertically with cylindrical bores 84 and 85 the axis of which coincides with the pump axis. The rotor is capable of rotation about this axis. Upper bore 84 forms an opening through which spindle 48 and the parts attached thereto may be inserted or withdrawn when link 52 is uncoupled. Lower bore 85 forms tached toja corresponding boss on the casing and projecting through a hole in same to enable pinion I03 to mesh with ring gear 98. The com- Dlete driving unit may be removed without dis- I turblng the internal driving parts.

The driving. stroke producing and shifting mechanisms are all housed inside the casing for the purpose of protection and in order to permit a bearing for crosshead 64 operating the linkage connecting with collar 59 on spindle 48 and is provided with a keyway 89 in which slides the longitudinal key in rim 85 of crosshead 64. Rotor 83 is mounted in two large ball bearings 85 and 81, the lower'of which .is seated in a diaphragm forming part of the main casing, the upper one being seated in a removable spider 88 bolted to a rim around inside of the casing. On the upper portion of rotor 83 there is detachably mounted a ring-like member 88 with teeth on its under face forming the driven member of a pair of bevel gears. Power supplied through this gear serves to rotate the rotor 83. By unfastening the spider. the whole rotor and the other parts associated therewith may be removed after uncoupling from the lower lever I1, sufficient clearance being allowed through the hole in rim 9| to which spider 8-9 is attached.

Referring now more particularly to Figs. 6

and I, it will be readily observed that rotor 83 is provided with two 'swelllngs 82 and 93 on opposlte sides of the rotor extending inwardly with portions of cylindrical-shaped seats 84 in which blocks are secured by countersunk head bolts 95. Blocks 88 are provided with flat, oppositely disposed faces in vertical planes, with cylindrical backs and have length greater than the limit of swing of spindle 48 in way of driving wheel 55. These blocks are spaced apart far enough to receive between them driving wheel 55, and serve to transmit the driving torque from rotor 83 to spindle 48 through normal contact with driv ng wheel 55.

Holes 91 of suitable form are provided in the walls of rotor 83 for access to forked link 62 to couple or to uncouple the same and holes 98 for a boring bar used in machining cylindrical block seats. Two adjustment screws 98 and I80 form stop limits for the spindle swing, the first for the "no stroke position and the other for the full stroke position. v

The power input to drive the pump may be of any constant speed type and is applied to shaft IIII extending from the outside of easing I82 to pinion member I83 of the bevel gear set. Al though the driving shaft IN and, pinion I03 are illustrated as formed in a single piece, they may be rigidly connected separate parts, if desired.

The bevel gear set constituted of I83 and 88 provides a reduction in gearing to conform to the relative speeds of revolution of the power source and of the pump. Driving shaft [BI is mounted in ball bearings I84 and is seated in a cylindrical quill I85 having a flange I88 adapted to be atprofuse lubrication thereof by oil circulating means of the cascade. type (not shown). A suitable number of hand holes I81, I88, and I88; with detachable covers are provided in the walls of the casing to permit ready access to the inner mechanism. Casing I02 itself is substantially of a rectangular prism form having a flanged base and being divided internally into three compartments by means of diaphragm 88 and spider 88 referred to hereinabove. The uppermost one of these compartments contains the major portion of wobble plate 28, sockets 42, connecting rods 45 and universal joint 33. The intermediate chamber contains driving gears I83 and 88, rotor 83, wobble plate spindle 48 and shifting linkage 82, while the lower compartment contains shifting lever I1 and pump (not shown) The oil circulating pump may be driven from a gear mounted on the outside diameter of the skirt portion of rotor 83 projecting below lower ball bearing 81. The lower compartment of the casing also serves as an oil sump from which the oil pump suction may take its supply and to which drains the oil fed to the top by the pump, suitable leaders being provided for proper distrlbution to the various operative parts.

From the preceding description the operation of my improved pump will be readily understood by those skilled in the art. when power is applied to rotate shaft IIII and pinion I83, gear 98 and rotor 83 will be caused to revolve about the vertical pump axis. Fig. 10 shows the spindle 48 in the perpendicular or "no, stroke" position with link 82, crosshead 84, forked shaft I4 and lever 11 in their corresponding relationship. Since the spindle axis and rotor axis coincide,

. there will be no movement of the wobble plate,

hence no stroke of the plungers and no delivery from the pump. placed fromthe perpendicular, the driving wheel 55 meanwhile rolllngoutwardly alonglthe flat face of one of blocks 88 until the desired maximum limit has been obtained. Whether the one or the other of the :blocks is operative, depends on the direction of rotation. either direction being effective. Thus, the lower end of spindle 48 will be forced to travel alonga circular path being retained at a constant radial distance from the central axis by linkage 52 as long as control shaft 11 remains stationary. Spindle 48 does not revolve around its own axis due to the constraint of universal joint 33 from which the "wobble plate is suspended, although free to assume an angular relationship to thepump axis. This movement'of spindle 48 causes the rim of wobble plate 38 to oscillate universally about center of universal joint 33 in this way producing an upward movement of plungers through the medium of connecting rods 45 during one half oscillation and a downward movement during the second half Oscillation.

The magnitude of this up and down movement, in other words the length of the stroke of the plungersis proportionate to the oil! center position of spindle 45 at location of driving wheel 55. It will be noted that as rotor 83 with keyed crosshead 64, link 62 and collar 53 is revolving The spindle 48 may be dis-.

about the pump axis, there occurs a relative rotation between the rotationlessly mounted spindle 40 and collar 59 and also between spindleand driving wheel 55. This accounts for the use of roller or ball bearings 51 and 60 in order to minimize friction between these parts. transmitting substantial forces perpendicular to the spindle axis while rotating. The two forces contemplated, however, are in planes at right angles to one another. The nature of the construction is such that movement of the spindle to and from the central pump axis may be accomplished while the pump is running-continuously whereby the delivery capacity may be varied from zero to the maximum delivery for whichthe pump is designed.

It will be noted that the pump embodying the principles of the present invention provides a number of important advantages. First of all, my improved pump is extremely flexible in operation and the rate of delivery may be readily controlled from zero up to a desired maximum while the pump is running continuously. This is readily accomplished through the medium of the control shaft extending to the outside of the casing where it can be provided with a suitable mechanism operated manually by the operator or by an automatic apparatus responsive to changes in delivery pressure. This automatic controlling apparatus may be arranged to function in such manner that the pump remains on full stroke until a predetermined pressure is reached and as the pressure rises above this point, it will progressively decrease the stroke until at a further predetermined pressure the stroke will have been reduced to substantially zero, and the pressure will be maintained without delivery. when the pressure is released, the stroke will be increased to its maximum again.

It is also to be observed that my improved pump is capable of generating much higher pressures than practically any of the conven-' tional variable delivery pumps of the swash plate" or of the radial, eccentrically displaceable types. This is principally due to my novel structural combination involving the use of packed plunger and poppet valve construction which are operating in a one-piece, forged steel pump body and due to the novel arrangement and separation of the pump body and of the operating mechanism into separate but operatively associated structures whereby the driving mechanism may readily be made of dimensions suitable for transmitting the imposed heavy loads resulting from these high pressures.

Another important advantage of my invention is that water as well as other liquids may be handled by the pump in contrast to all of the conventional variable delivery pumps which are restricted to the use of oil as pressure fluid, in view of the fact that due to their design the pressure fluid has at the same time to lubricate the revolving and reciprocating parts of the pump. My improved pump successfully 8111111? hates the cost, dirtiness and fire risks connected with the application of oil as fluid pressure me dium and also the heretofore unavoidable variations in efficiency caused by variations in the viscosity of the oil.

Moreover, due to the separation of the operating mechanism from the detachable pump body, pump bodies of different delivery capacities and having larger or smaller plungers may be atas the resulting total reaction and power requirement remains substantially constant. This is, of course, of very considerable practical and commercial value inasmuch as the operating mechanisms may be manufactured in quantities and pump bodies may be finished and attached thereto to suit customers individual requirements. In case it is desired to alter the delivery characteristics of an existing installation, a new pump body and different plungers may be substituted on the same operating mechanism. The design of my improved pump is so simple and so easily accessible that it may be adjusted and maintained by any competent engineer and does tached to the same operating mechanism so long 7 not require shipment of the whole unit back to the factory for adjustments and repairs.

The above advantages render my novel pump particularly suitable for several important applications such as supplying operating pressure fluid to hydraulic presses where a rapid advance with little load is followed by the application of heavy pressures at or near the end of their stroke, which pressure may be maintained for some time. Such is the case, for example, in molding presses where the material is cured for some time under heavy pressures. The pump embodying the invention may also be used in ships having hydraulic steering gear wherethe turning moment on the rudder stock is small at small angles of the rudder and increases rapidly towards the limit of the swing. Another important application of my improved pump is for high pressure boiler feed lines where varying demands call for corresponding variations in delivery, particularly in marine use where harbor stand by" service, maneuvering and full speed ahead call for a. wide range of delivery.

The pump embodying the principles of the present invention is capable of important modifications. Thus, special pump bodies may be employed in combination with the pump-actuating mechanism and may accommodate tandem or two-diameter plungers. This modification makes it possible to supply a relatively large volume of low-pressure discharge by the pump up to a predetermined pressure, utilizing both the area of small diameter and the annular area between the two diameters, after which by suitable pressure-actuated means, the suction valves serving the annular pumping chambers will be unseated and retained in that condition. This allows fluid to circulate back and forth through these open valves without causing any delivery through the corresponding discharge valves, which act as checks to prevent subsequent high pressure generated by the small plungers from backing up into the suction supply. From this point onwards, the small plungers will act alone and pressure reaches the next predetermined limit, their stroke will be governed by the pressurecontrol mechanism, same as in the practical embodiment of the invention described in the foregoing. When the pressure has been reduced to the lower range again, the suction valves held in. their open position will be allowed to seat in the lower portion of the pump body.

operative and the final heavy pressure demands would beserved by the supply from the small plungers.

This special pump body may be installed on the standard operating mechanism, with longer attachment studs and longer plungers, to allow space for the low pressure suction valve-tripping or unloading mechanism'to be installed on the underside of the pump body. I v

The construction and the operation of this modified embodiment of the invention will be best understood by referring ,to Figs. 11, 12 and 13 of the drawings. Essentially, a pump body la is provided comprising formations similar to those of pump body I illustrated in Fig. 1, such as a square-shaped lower portion 2a surmounted by a cylindrical portionBa of reduced diameter but substantially deeper than 3 in Fig. 1, again surmounted by a second cylindrical portion 40. of further reduced diameter'of approximately the same depth as 4 in Fig.1. In pump body la the same plurality of pumping chambers 5a, suction valves Illa, discharge valves IIa, suction passages I3a, suction compartment I5a, chambers IIa, horizontal passages Ilia, discharge passages IBa, central chamber 20a, closures 22a, all disposed substantially as in the basic design, and performing the same functions of governing the flow of liquid from suction chamber to discharge. These elements will be best observed in Fig. 13 where the reduced diameter portion 9a. of the two diameter plunger acts to generate the high pressure flow corresponding to the plunger 9 in Fig. 1. Similar guide bushings 6a, packings Ia of the leather, non-adjustable type,

and retaining glands 8a serve to confine the high-pressure liquid in its proper channels and to prevent leakage into the low pressure areas. However, such leakage, if any, does no harm and merely decreases the volumetric efiiciency of high pressure delivery. I

Referring now more particularly to Fig. .12, the additional elements for supplying the low pressure liquid comprise suction chamber I5a, suction passage I3a, suction valve Iflb, horizontal passage Iflb, pumping chamber 5b, vertical riser 50 to discharge valve IIb and horizontal passage I9a to central chamber 20a. Closures 22b are provided for sealing the space above the valves IIlb andI lb. The low pressure pumping action is accomplished by the annular area between the large diameter portion 9b and small diameter portion 9a of the two diameter plunger. Bushings 6a, packings 1a and glands 8a serve to prevent leakage past the plunger. The relative po- 'sition of the two sets of valves can be readily seen from Fig. 11 which is a plan view of the p m y- The mechanism for actuating and disabling the low pressure elements at predetermined pressures comprises a vertical central passage III! which connects chamber 200. with a chamber II I A plunger II2 projects into chamber III and extends through suitable bushing H3, packing Ill and gland I I5 to the outside of pump body. The outer end of plunger H2 is preferably expanded into a mushroom-shaped head resting on tips I I5 01 multiple-pivoted levers I I1, preferably three or more, which are uniformly spaced around the central axis of the pump and extend radially outward. Levers I" are suspended in suitable pivot brackets II8 attached to the underside of the pump body.

At the outer ends of levers III are disposed compression springs IIB opposing the movement of plunger II2. Springs IIB are provided with adjustable abutments I2II in anchorages I2l by means of which varying desired compression of the springs may be obtained.

At such distance outwardly from the pump axis that they will come vertically under suction chamber I5a, adjustable tappets I22 are inserted through levers 1. These tappets thrust against plungers I23 extending through suitable glands I24 and packings I25 to the inside of suction chamber I511.

The upper ends of plungers I23 support and, when actuated, lift a continuous ring-shaped member I26 inserted in the suction chamber before closure Ha is secured in place. Cylindrical pockets I21 having vertical axes are provided.

in the rings at such circumterentially spaced intervals that their axes coincide with the vertical axes of low pressure suction valves IIlb. At their bottom end, these pockets are provided with detachable closures I28 retaining compression springs I29 pressing on their upper ends yield as the ring moves upwards.

against the enlarged diameter portion of plungers I30, the smaller diameter portion of which extends upwards through the ring I26 to within a short distance of the underside of suction valves IIlb.

From the preceding description operation of this modified embodiment of the invention will be readily understood by those skilled in the III, and since tappets I22 are on the same side of the pivot as the springs, they are in a lowered position allowing ring I26 to remain inthe lowered position. When sufficient pressure has been generated in the discharge chamber 200. acting through passage III! on upper end of plunger II2 to overcome the resistance of springs H9, plunger, II! will move outward and will lift ring I26,unti1 plungers I30 are forced against the underside of suction valves IIIb.

The object of the provision of springs I29 is now clearly apparent, since at any time during the pumping operation, some of the valves are closed with pressure on top of them while the remainder are lifted in the suction position.

Where the valves are in the lifted position, the

plungers move up and contact the valves, holding them in the raised position, spring I29 having sufficient power to sustain the weight of the valve and also to hold them open against the ensuing outrush of liquid during the succeeding discharge strokes of the annular portion of plungers 9b. On the other hand; when ring I26 is lifted and plungers I30 contact such valves "It: as are at that time serving as check valves against the discharge pressure, springs I29 will As the pump driving mechanism revolves bringing valves IIib successively into suction relationship, these valves will then be held open in turn by the expansion of springs I29 as the top load is removed from valves I b, until all of the valves I0b are out of action. This will occur in onehalf revolution of the drive mechanism.

The action of plungers 9a now continues alone, discharges valves I lb now acting .as check valves to prevent high pressure liquid from backing up into low pressure riser c, the liquid pumped by annular portion of plungers 9b now circulating back and forth through the held open valves Illb with each stroke of the plunger.

Whenever the delivery pressure drops sufficiently so that the load on plunger H2 is overbalanced by the power of spring II9, a reverse action of levers II'I takes place. Plunger II2 moves upward, tappets I22, plungers I23 and ring I26 drop down, permitting valves Illbto seat and normal pumping action of annular portion of plungers 9b is resumed, the discharge of both 9a and 9b then being combined at the lower pressure range.

Although the invention has been described in connection with a few preferred embodiments thereof, variations and modifications may be resorted to by those skilled in the art without de-' parting from the principles of the present invention.

In the foregoing description, I have disclosed a preferred embodiment of my invention in which the pistons of the pumping chambers and the actuating mechanism in the main casing are arranged in the vertical direction. It is to be noted, however, that the pump embodying the invention may be constructed so as to be arranged and actuated in the horizontal direction with equal or similar results. Furthermore, instead of having the shaft of the driving motor at right angles to the vertical axis of the pump, the pump may be driven by means of a motor having its axis parallel to that of the pump and directly driving the end of the spindle of the wobble plate whereby no gear transmission is necessary between the motor and the actuating mechanism of the pump.

I consider all of these variations and modifications as within the true spirit and scope of the invention as disclosed in the present description and defined by the appended claims.

I claim:

1. In a multiple-plunger, variable delivery pump, the combination comprising a pump body having a plurality oi. pumping chambers concentrically positioned about a central axis, each of said pumping chambers having a small diameter and a large diameter portion, a reciprocable twodiameter plunger in each 01' said pumping chambers, high-pressure suction and discharge check valves for the small diameter portion of each of said chambers, low-presure suction and discharge check valves for the large diameter portion of, each of said chambers, a control plunger displaceably mounted in the central portion of said pump body and under the eiIect of discharge fluid, a plurality of levers having one of their ends pressing against said control plunger, resilient means acting on the other end of said levers, an annular suction compartment for said suction valves, a ring-shaped valve control member in said suction compartment adapted to be displaced to engage a said low pressure suction valves and to displace the same into an inoperative position, and means operable by said levers to displace said valve control member whereby said low pressure suction valves will be displaced into an inoperative position by said valve control member after a predetermined fluid discharge pressure has been exceeded and said valves will be returned into their operative position after the pressure of said fluid has decreased below said predetermined pressure.

2. In a multiple-plunger, variable delivery pump, the combination comprising a pump body having a plurality of pumping chambers concentrically positioned about a central axis, each of said pumping chambers having a small diameter and a large diameter portion, a reciprocable two-diameter plunger in each of said pumping chambers, high-pressure suction and discharge check valves for the small diameter portion of each of said chambers, low-pressure suction and discharge check valves for the large diameter portion of each of said chambers, a control plunger displaceably mounted in the central portion of said pump body and under the eifect of discharge fluid, a plurality of levers having one of their ends pressing against said control plunger, resilient means acting on the other end of said levers, an annular suction compartment located underneath and communicating with said suction valves, a valve control ring in said suction compartment adapted to be displaced to engage said low-pressure suction valves and to displace the same into an inoperative position, means operable by said levers to displace said valve control ring whereby said low-pressure suction valves will be displaced into an inoperative position by said valve control ring after a predetermined critical fluid discharge pressure has been exceeded ,and said valves will be returned into their operative position after the pressure of said fluid has decreased below said critical pressure, and means for adjusting the resiliency of said resilient means.

'3. In a multiple-plunger, variable delivery pump, the combination comprising a pump body having a plurality of pumping chambers concentrically positioned about a central axis, each of said pumping chambers having a small diameter and a large diameter portion, a reciprocable two-diameter plunger in each of said pumping chambers, high-pressure suction and discharge check valves for the small diameter portion of each of said chambers, low-pressure suction and discharge check valves for the large diameter portion of each of said chambers, a control plunger displaceably mounted in the central portion of said pump body and under the effect of discharge fluid, a plurality of levers having one of their ends pressing against said control plunger, resilient means acting on the other end of said levers, an annular suction compartment located underneath and communieating with said suction valves, a valve control ring in said suction compartment adapted to be displaced to engage said low-pressure suction valves and to displace the same into an inoperative position, means operable by said levers to displace said valve control ring whereby said low-pressure suction valves will be displaced into an inoperative position by said valve control ring after a predetermined fluid discharge pressure has been exceeded and said valves will be returned into their operative position after the pressure of said fluid has decreased below said predetermined discharge pressure, and individual resilient means intermediate to said valve control ring and each of said suction valves to delay disabling displacement of said low-pressure suction valves until such time as said valves are free from the pressure of discharging fluid.

4. In a multiple-plunger, variable delivery pump, the combination comprising a pump body said chambers, low-pressure suction and discharge check valves for the large diameter portion of each of said chambers, a control plunger displaceably mounted in the central portion of said pump body and under the effect of discharge fluid, a plurality of levers having one of their ends pressing against said control plunger, resilient means acting on the other end of said levers, an annular suction compartment located underneath and communicating with said low-pressure suction valves, a. valve control ring in, said suction compartment, a valve control plunger for each of said valves resiliently held in said ring and adapted to displace said valves into their inoperative position when said ring is raised, and means operable by said levers to raise said ring whereby said low-pressure suction valves will be displaced into their inoperative position by said valve control 'ring after a predetermined fluid "discharge pressure has been exceeded and said valves will be returned into their operative position after the pressure of said fluid has decreased below said critical discharge pressure, said disabling displacement of the lowpressure suction valves being dependent on the absence of pressure on the individual valves.

FRANK L. DAVIS, JR. 

